NCERT Class 10 Science Science: Chapter 8 — Heredity
This NCERT Class 10 Science chapter, Heredity, explores the mechanism by which variations are created and inherited. It explains that while asexual reproduction produces similar individuals with minor variations due to DNA copying inaccuracies, sexual reproduction generates greater diversity. The chapter discusses how inheritance from previous generations provides a basic body design with subtle changes for the next. It highlights that not all variations have equal chances of survival; environmental factors select variants, forming the basis for evolution. The chapter introduces the concept of heredity, defining it as the process by which traits are reliably inherited from parents to offspring. It uses examples like earlobe types to illustrate inherited traits and introduces Mendel's contributions to understanding the rules of inheritance, emphasizing that both parents contribute genetic material influencing traits.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 10 |
| Subject | Science |
| Book | Science |
| Chapter | Chapter 8 — Heredity |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 5 minutes |
| Word count | 804 |
Learning outcomes
- Understand the concepts of heredity and variation.
- Explain how variations are created during reproduction.
- Recognize the role of environmental factors in the selection of variations.
- Identify inherited traits and their patterns of inheritance.
- Learn about Mendel's contributions to the study of heredity.
Vocabulary
| Word | Meaning |
|---|---|
| Heredity | The process by which traits and characteristics are reliably inherited from parents to offspring. |
| Variation | Differences among individuals of a species, arising from genetic mutations and recombination. |
| Asexual Reproduction | Reproduction that involves a single parent and produces offspring genetically identical to the parent. |
| Sexual Reproduction | Reproduction that involves two parents contributing genetic material to produce offspring that are genetically unique. |
| Traits | Specific characteristics of an organism, such as eye color or earlobe type. |
| Inheritance | The passing of traits from parents to their offspring. |
| DNA copying | The process by which genetic material (DNA) is replicated before cell division. |
| Environmental factors | Elements in the surroundings that can affect the survival and reproduction of organisms. |
| Evolutionary processes | The mechanisms by which species change over time, driven by factors like natural selection. |
| Earlobe types | Variations in the attachment of the lower part of the ear to the head (free or attached). |
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Practice questions
- If a trait exists in 10% of an asexually reproducing population and another trait exists in 60%, which trait is likely older? Answer: The trait existing in 60% of the population is likely to have arisen earlier, as it has had more time to spread.
- How do variations in a species help in its survival? Answer: Variations provide different advantages, allowing some individuals to survive better in specific environmental conditions, thus promoting the survival of the species.
- What determines the process by which traits are inherited? Answer: The rules of heredity determine the process by which traits and characteristics are reliably inherited.
- What are the two types of earlobes mentioned in the chapter? Answer: The two types of earlobes mentioned are free earlobes and attached earlobes.
Frequently asked questions
What is heredity?
Heredity is the process by which traits and characteristics are reliably inherited from parents to their child.
How does variation occur during reproduction?
Variations occur due to minor inaccuracies in DNA copying during asexual reproduction and greater diversity is generated during sexual reproduction.
Do all variations help a species survive?
No, depending on the nature of variations, different individuals have different advantages. Environmental factors select variants that are better suited for survival.
Who worked out the main rules of inheritance?
Gregor Mendel worked out the main rules of inheritance.
What is the significance of variations for a species?
Variations are crucial for the survival of a species as they provide different advantages, allowing some individuals to survive better in changing environmental conditions and forming the basis for evolution.
What are inherited traits?
Inherited traits are characteristics that are passed down from parents to their offspring through genetic material.
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Topics covered
NCERT Class 10 Science — Science — Chapter 8 — Heredity. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.